Q1. What is the atomic mass for potassium?

Background

Topic: Periodic Table & Atomic Mass

This question tests your knowledge of the periodic table and the concept of atomic mass, which is the weighted average mass of an element's isotopes.

Key Terms:

• Atomic mass: The average mass of atoms of an element, measured in atomic mass units (amu).

• Potassium (K): An element with symbol K.

Step-by-Step Guidance

1. Locate potassium (K) on the periodic table.

2. Identify the atomic mass value listed for potassium.

3. Compare the answer choices to the atomic mass value you found.

Try solving on your own before revealing the answer!

Q2. Which of the following is an ionic compound?

Background

Topic: Types of Chemical Bonds

This question tests your ability to distinguish between ionic and covalent compounds based on their composition.

Key Terms:

• Ionic compound: Formed from the transfer of electrons between a metal and a nonmetal.

• Covalent compound: Formed from the sharing of electrons between nonmetals.

Step-by-Step Guidance

1. Identify which elements in each formula are metals and which are nonmetals.

2. Recall that ionic compounds are typically formed between metals and nonmetals.

3. Look for a compound in the list that fits this pattern.

Try solving on your own before revealing the answer!

Q3. Without using a calculator, solve the following problem:

Background

Topic: Scientific Notation & Exponents

This question tests your ability to manipulate scientific notation and exponents without a calculator.

Key Terms and Formulas:

• Scientific notation: Expressing numbers as .

• Exponent rules: ; ;

Step-by-Step Guidance

1. Multiply and using exponent rules.

2. Raise the result to the power of 2.

3. Divide by using exponent subtraction.

4. Set up the final exponent calculation for the last step.

Try solving on your own before revealing the answer!

Q4. Identify the common substance that has the lowest density.

Background

Topic: Density

This question tests your understanding of density and your ability to compare common substances.

Key Terms:

• Density:

• Common substances: sugar, ethanol, table salt, aluminum, titanium

Step-by-Step Guidance

1. Recall the typical densities of each substance listed.

2. Compare the densities to determine which is lowest.

3. Consider that metals generally have higher densities than organic compounds.

Try solving on your own before revealing the answer!

Q5. Which of the following contains the fewest atoms? (10.0 g samples of Kr, Li, Ar, Na, Cs)

Background

Topic: Moles, Atomic Mass, and Counting Atoms

This question tests your ability to relate mass, atomic mass, and the number of atoms in a sample.

Key Terms and Formulas:

• Mole: atoms

• Number of atoms:

Step-by-Step Guidance

1. Find the atomic mass for each element listed.

2. Calculate the number of moles in 10.0 g for each element using .

3. Multiply the number of moles by Avogadro's number to get the number of atoms.

4. Compare the results to determine which sample has the fewest atoms.

Try solving on your own before revealing the answer!

Q6. Identify the element that has an atomic number of 15.

Background

Topic: Periodic Table & Atomic Number

This question tests your knowledge of the periodic table and the concept of atomic number, which is the number of protons in an atom.

Key Terms:

• Atomic number: The number of protons in the nucleus of an atom.

Step-by-Step Guidance

1. Locate atomic number 15 on the periodic table.

2. Identify the element corresponding to atomic number 15.

3. Compare the answer choices to the element you found.

Try solving on your own before revealing the answer!

Q7. Choose the homogeneous mixture from the list below.

Background

Topic: Mixtures – Homogeneous vs. Heterogeneous

This question tests your ability to distinguish between homogeneous and heterogeneous mixtures.

Key Terms:

• Homogeneous mixture: A mixture with uniform composition throughout.

• Heterogeneous mixture: A mixture with non-uniform composition.

Step-by-Step Guidance

1. Review the definitions of homogeneous and heterogeneous mixtures.

2. Consider the appearance and composition of each option.

3. Identify which mixture is uniform throughout.

Try solving on your own before revealing the answer!

Q8. Cesium belongs to which group of the periodic table?

Background

Topic: Periodic Table Groups

This question tests your knowledge of the periodic table and the classification of elements into groups.

Key Terms:

• Alkali metals: Group 1 elements

• Halogens: Group 17 elements

• Noble gases: Group 18 elements

• Alkaline earth metals: Group 2 elements

Step-by-Step Guidance

1. Locate cesium (Cs) on the periodic table.

2. Identify which group it belongs to.

3. Compare the answer choices to the group you found.

Try solving on your own before revealing the answer!

Q9. Which one of the following compounds contains ionic bonds?

Background

Topic: Chemical Bonding

This question tests your ability to identify ionic compounds based on their constituent elements.

Key Terms:

• Ionic bond: Formed between a metal and a nonmetal.

• Covalent bond: Formed between two nonmetals.

Step-by-Step Guidance

1. Identify which compounds contain a metal and a nonmetal.

2. Recall that ionic bonds are formed between metals and nonmetals.

3. Compare the answer choices to find the compound with ionic bonds.

Try solving on your own before revealing the answer!

Q10. Which of the following exists as a polyatomic molecule?

Background

Topic: Molecular Structure

This question tests your knowledge of elements that form polyatomic molecules (more than two atoms bonded together).

Key Terms:

• Polyatomic molecule: A molecule consisting of more than two atoms.

Step-by-Step Guidance

1. Recall which elements naturally form polyatomic molecules.

2. Consider the molecular forms of each element listed.

3. Identify the element that forms a polyatomic molecule.

Try solving on your own before revealing the answer!